Process for the production of malleable iron direct from ore.



. I A. R. LINDBLAD. I

PROGESS FOR THE PRODUCTION OF MALLEABLE IRON DIRECT FROM ORE.

APPLICATION FILED JULY 16, 1910.

1,058,991, 7 Patented Apr. 15, 1913 v V v" v EATER 3 w/ rzva-sas V Va?70)? MM Arzr UNITED STATES PATENT OFFICE.

AXEL RUDOLF LINDBLAD, OF LUDVIKA, SWEDEN.

PROCESS FOR THE PRODUCTION OF MALLEABLE IRON DIRECT FROM ORE.

Specification of Letters Patent.

Patented Apr. 15, 1913.

application filed July 16. 1910. Serial No. 572,328.

To all whom. it may concern:

Be it known that I, Axnt. Rimonr LIND- BLAI), engineer, a subject of theKing of Sweden, residing at Ludvika, in the Kingdom of Sweden, haveinvented certain new and useful Improvements in Processes for theProduction of Malleable Iron Direct from Ore, of which the following isa specification.

The present invention relates to a method for producing malleable irondirect from ore.

The characteristic feature of the invention is that the ore, mixed witha small amount of reducing materials, is charged into a shaft in formresembling an ordinary blastfurnace shaft. Experience has shown that forobtaining complete reduction more easily it is necessary to mix the orewith a small amount of reducing materials. In this shaft the ore isexposed to the-action of reducing gases whereby the said ore isentirely, or at least to a great extent transformed into iron sponge.This iron sponge is then caused without its cooling or coming in contactwith the air to descend (or it may be raked down) into an electricfurnace directly communicating with said shaft in which furnace the ironsponges are melted. In this manner malleable iron can be pro duced by acontinuous process direct from ore.

Furnaces of various constructions can, of

' furnace which may be used for carrying out the present process. Thisform of the furnace is, however, only to be regarded as an example givenwith the object of elucidating the description.

As shown by the drawing, the furnace consists of a reduction shaft 1,which is car-. ried by an iron structure 2. Under the shaft there is anelectric melting-furnace 3. In the arch 4 which covers the electricfurnace or melting chamber there is an opening through which the lowerpart of the shaft communicates with the interior of the electricmelting-furnace. 5 isa furnace mouth of well known construction; 6 areoutlets for the gases leaving the shaft; 7 are nozzles through whichreducing gases can be forced into the furnace, 8 are electrodes throughwhich the electric energy is supplied to the melting furnace and anapparatus hereinafter described, as employed for generating orregenerating the said reducing gases.

The course of the process is in substance as follows: The shaft ischarged with ore with the requisite fluxes, and with coke or charcoal.Through the nozzles 7 is blown in a reducing gas, through the agency ofwhich the ore. to a great extent at any rate. is reduced. The ironsponge thus obtained passes through the opening in the. arch of themelting furnace down into the electric furnace chamber 3, where it meltsthrough the action of the electric current, whereupon the malleable ironthus obtained can be tapped off through the discharge opening 12.

The reducing gases blown into the shaft can be produced in ordinary gasgenerators, or in some other suitable manner. They can also be obtainedby the regeneration of the gases leaving the reduction shaft, whichregeneration takes place in a special apparatus. This latter methodaffords the advantage that the gases are practically free from nitrogen.

In the drawing is shown that the gases are blown into the electricmelting furnace in the free spaces which in the furnace drawn arisebetween the upper sloping surface (indicated with dotted lines 14) ofthe material into the furnace and the furnace arch 4. From these freespaces the gases then make their Way up the shaft. A necessary conditionfor the application of this arrangement is, however, that the electrodesenter into the material in the melting furnace and do not form freeelectric light arcs. If such electric arcs were formed, the gasesblown-in would by said arcs be heated to a far too great ex tent. It is,however, naturally by no means necessary that the gases should be blownin in this manner; they may also very well be blown in directly into thelower part of the shaft through the twyers 15 indicated in dotted lines,or in some other manner. The gases to be blown into the furnace areheated or warmed up in a special apparatus, such as the heater shown inthe drawing. .This apparatus is connected ttrthe outlet-pipe 6 andnozzle 7 by means of the pipe 7-. This warming-up may be carried out byelectricity or in any of the ways which have hitherto been in commonuse. The reducing gases obtained 2C0.

the hotter part of the furnace is kept at a higher percentage ofcarbonic monoxid. which is particularly favorable for the process ofreduction. The quantity of carbon which should be charged together withthe ore depends on the nature and quantity of the gas blown in; thetemperature in the reducing furnace, etcetera, factors which must bedeterminedfor each separate case.

In the construction of furnace shown by way of example on the drawing,the reducplaced by the side of the reducing furnace,

from the latter furnace ing shaft is placed above the melting furnace.By its being so placed, the process is facilitated in so far as thereduced char 'e sinks down into the melting chamber-of 1ts own accord.This, however, is not a necessary condition for carrying out theprocess. The melting-furnace. may very well be but then the materialmust as a rule be raked into the former. The course of the process may,as far as the reducing furnace is concerned, be regulated by thequantity and nature of the gas blown in, by its'heating and by thenature of the materials charged and the manner, in which they arecharged. In the meltingchamber the process is regulated by thecontrolling of the supply of electric energy. In case the gases are madeto pass the meltingfurnace before they enter the sh-aftorreducingfurnace they, of course, also influence the course of the process in themelting furnace. The greatest advantage gained by the process thusdescribed is that malleable iron can beproduced directly from ore in .acontinuous process, whereby the costs. for the ready material will beconsiderably lower than with processes hitherto used.

Experiments have before been made to combine a Lancashire hearth with areducing furnace so that the reducedmaterial descended direct from thelatter into the former. The method tried, however, did not proveto beeconomical, as the product thus obtained needs in any case to beremelted for making it homogenous and free from slag. These drawbacks donot attach to the process here described, as the product ishere obtainedfrom-the furnace in a molten condition, and thus free from slag andcomparatively homogenous.

A proposal has also been brought forward 'to reduce iron ore in ashaft-formed meltshaft. A process of this kind, however, is

obviously attended by the inconvenience that.

it is diflicult to keep the temperature in the lower part of the furnacehigh enough for soft iron to be tapped ofl", but at the same time thesaid temperature will be unnecessarily high for the reduction. Thesedifliculties are completely eliminated in the rocess 'here described, asthe reduction an the -melting take place in furnaces or chambers which,though in communicationwith one another, are distinctly separate. Thetemperature in the melting-furnace can thus be kept up at the requisiteheight, without the reducing shaft becoming more heated than isdesirable. The gases blown in pass in the present process not near themelted products in the melting-chambers, but in any case only throughthe free space in the upper part of the furnace.

Having thus described my invention, I declare, that what I claim is 1.The herein described process for the production of malleable iron directfrom ore which consists in charging a mixture of ore and reducingmaterial into a shaft furnace, heating gases, taken out from the shaft,outside the furnace, introducing said heated gases into the shaft,whereby the ore is fully or partially reduced, causing the mass thusobtained to pass without cooling or coming in'contact with the air intoan electric melting furnace and melting said mass.

2. The herein described process for the production of malleable irondirect from ore which consists in charging a mixture of ore and reducingmaterial into a shaft'furnace,

heating gases, taken out from the shaft, outside the furnace,introducing said heated gases into a melting chamber, communicating withthe furnace, wherefrom it is allowed to pass into contact with thecharge the shaft, whereby the ore is fully. or partially reduced,causing the mass thus obtained to pass without cooling or coming incontact with the air into the electric and melting said mass.

' In witness whereof -I have hereunto set.

my hand in resence of two witnesses.

.AX L RUDOLE LINDBLAD. Witnesses:

S.- Nxs'rsn'r, Env. OLANSSON.

melting furnace

